Understanding how individualised physiotherapy or advice altered different elements of disability for people with low back pain using network analysis

Purpose

The Oswestry Disability Index (ODI) is a common aggregate measure of disability for people with Low Back Pain (LBP). Scores on individual items and the relationship between items of the ODI may help understand the complexity of low back disorders and their response to treatment. In this study, we present a network analysis to explore how individualised physiotherapy or advice might influence individual items of the ODI, and the relationship between those items, at different time points for people with LBP.

Methods

Data from a randomised controlled trial (n = 300) comparing individualised physiotherapy versus advice for low back pain were used. A network analysis was performed at baseline, 5, 10, 26 and 52 weeks, with the 10 items of the Oswestry Disability Index modelled as continuous variables and treatment group (Individualised Physiotherapy or Advice) modelled as a dichotomous variable. A Mixed Graphical Model was used to estimate associations between variables in the network, while centrality indices (Strength, Closeness and Betweenness) were calculated to determine the importance of each variable.

Results

Individualised Physiotherapy was directly related to lower Sleep and Pain scores at all follow-up time points relative to advice, as well as a lower Standing score at 10-weeks, and higher Lifting and Travelling scores at 5-weeks. The strongest associations in the network were between Sitting and Travelling at weeks 5 and 26, between Walking and Standing at week 10, and between Sitting and Standing scores at week 52. ODI items with the highest centrality measures were consistently found to be Pain, Work and Social Life.

Conclusion

This study represents the first to understand how individualised physiotherapy or advice differentially altered disability in people with LBP. Individualised Physiotherapy directly reduced Pain and Sleep more effectively than advice, which in turn may have facilitated improvements in other disability items. Through their high centrality measures, Pain may be considered as a candidate therapeutic target for optimising LBP management, while Work and Socialising may need to be addressed via intermediary improvements in lifting, standing, walking, travelling or sleep. Slower (5-week follow-up) improvements in Lifting and Travelling as an intended element of the Individualised Physiotherapy approach did not negatively impact any longer-term outcomes.

Trials registration

ACTRN12609000834257.

How does individualised physiotherapy work for people with low back pain? A Bayesian Network analysis using randomised controlled trial data

PURPOSE

Individualised physiotherapy is an effective treatment for low back pain. We sought to determine how this treatment works by using randomised controlled trial data to develop a Bayesian Network model.

METHODS

300 randomised controlled trial participants (153 male, 147 female, mean age 44.1) with low back pain (of duration 6-26 weeks) received either individualised physiotherapy or advice. Variables with potential to explain how individualised physiotherapy works were included in a multivariate Bayesian Network model. Modelling incorporated the intervention period (0-10 weeks after study commencement-"early" changes) and the follow-up period (10-52 weeks after study commencement-"late" changes). Sequences of variables in the Bayesian Network showed the most common direct and indirect recovery pathways followed by participants with low back pain receiving individualised physiotherapy versus advice.

RESULTS

Individualised physiotherapy directly reduced early disability in people with low back pain. Individualised physiotherapy exerted indirect effects on pain intensity, recovery expectations, sleep, fear, anxiety, and depression via its ability to facilitate early improvement in disability. Early improvement in disability, led to an early reduction in depression both directly and via more complex pathways involving fear, recovery expectations, anxiety, and pain intensity. Individualised physiotherapy had its greatest influence on early change variables (during the intervention period).

CONCLUSION

Individualised physiotherapy for low back pain appears to work predominately by facilitating an early reduction in disability, which in turn leads to improvements in other biopsychosocial outcomes. The current study cannot rule out that unmeasured mechanisms (such as tissue healing or reduced inflammation) may mediate the relationship between individualised physiotherapy treatment and improvement in disability. Further data-driven analyses involving a broad range of plausible biopsychosocial variables are recommended to fully understand how treatments work for people with low back pain.

TRIALS REGISTRATION

ACTRN12609000834257.

The Evolving Case Supporting Individualised Physiotherapy for Low Back Pain

Low-back pain (LBP) is one of the most burdensome health problems in the world. Guidelines recommend simple treatments such as advice that may result in suboptimal outcomes, particularly when applied to people with complex biopsychosocial barriers to recovery. Individualised physiotherapy has the potential of being more effective for people with LBP; however, there is limited evidence supporting this approach. A series of studies supporting the mechanisms underpinning and effectiveness of the Specific Treatment of Problems of the Spine (STOPS) approach to individualised physiotherapy have been published. The clinical and research implications of these findings are presented and discussed. Treatment based on the STOPS approach should also be considered as an approach to individualised physiotherapy in people with LBP.

Development of a Multivariate Prognostic Model for Pain and Activity Limitation in People With Low Back Disorders Receiving Physiotherapy

OBJECTIVE

To identify predictors for back pain, leg pain, and activity limitation in patients with early persistent low back disorders (LBDs).

DESIGN

Prospective inception cohort study.

SETTING

Primary care private physiotherapy clinics in Melbourne, Australia.

PARTICIPANTS

Individuals (N=300) aged 18-65 years with low back and/or referred leg pain of ≥6 weeks and ≤6 months duration.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Numeric rating scales for back pain and leg pain as well as the Oswestry Disability Scale.

RESULTS

Prognostic factors included sociodemographics, treatment related factors, subjective/physical examination, subgrouping factors, and standardized questionnaires. Univariate analysis followed by generalized estimating equations were used to develop a multivariate prognostic model for back pain, leg pain, and activity limitation. Fifty-eight prognostic factors progressed to the multivariate stage where 15 showed significant (P<.05) associations with at least 1 of the 3 outcomes. There were 5 indicators of positive outcome (2 types of LBD subgroups, paresthesia below waist, walking as an easing factor, and low transversus abdominis tone) and 10 indicators of negative outcome (both parents born overseas, deep leg symptoms, longer sick leave duration, high multifidus tone, clinically determined inflammation, higher back and leg pain severity, lower lifting capacity, lower work capacity, and higher pain drawing percentage coverage). The preliminary model identifying predictors of LBDs explained up to 37% of the variance in outcome.

CONCLUSIONS

This study evaluated a comprehensive range of prognostic factors reflective of both the biomedical and psychosocial domains of LBDs. The preliminary multivariate model requires further validation before being considered for clinical use.

Who Benefits Most From Individualized Physiotherapy or Advice for Low Back Disorders? A Preplanned Effect Modifier Analysis of a Randomized Controlled Trial

STUDY DESIGN

A preplanned effect modifier analysis of the Specific Treatment of Problems of the Spine randomized controlled trial.

OBJECTIVE

To identify characteristics associated with larger or smaller treatment effects in people with low back disorders undergoing either individualized physical therapy or guideline-based advice.

SUMMARY OF BACKGROUND DATA

Identifying subgroups of people who attain a larger or smaller benefit from particular treatments has been identified as a high research priority for low back disorders.

METHODS

The trial involved 300 participants with low back pain and/or referred leg pain (≥6 wk, ≤6 mo duration), who satisfied criteria to be classified into five subgroups (with 228 participants classified into three subgroups relating to disc-related disorders, and 64 classified into the zygapophyseal joint dysfunction subgroup). Participants were randomly allocated to receive either two sessions of guideline based advice (n = 144), or 10 sessions of individualized physical therapy targeting pathoanatomical, psychosocial, and neurophysiological factors (n = 156). Univariate and multivariate linear mixed models determined the interaction between treatment group and potential effect modifiers (defined a priori) for the primary outcomes of back pain, leg pain (0-10 Numeric Rating Scale) and activity limitation (Oswestry Disability Index) over a 52-week follow-up.

RESULTS

Participants with higher levels of back pain, higher Örebro scores (indicative of higher risk of persistent pain) or longer duration of symptoms derived the largest benefits from individualized physical therapy relative to advice. Poorer coping also predicted larger benefits from individualized physical therapy in the univariate analysis.

CONCLUSION

These findings suggest that people with low back disorders could be preferentially targeted for individualized physical therapy rather than advice if they have higher back pain levels, longer duration of symptoms, or higher Örebro scores.

LEVEL OF EVIDENCE

2.

Variability in Strength, Pain, and Disability Changes in Response to an Isolated Lumbar Extension Resistance Training Intervention in Participants with Chronic Low Back Pain

Strengthening the lumbar extensor musculature is a common recommendation for chronic low back pain (CLBP). Although reported as effective, variability in response in CLBP populations is not well investigated. This study investigated variability in responsiveness to isolated lumbar extension (ILEX) resistance training in CLBP participants by retrospective analysis of three previous randomized controlled trials. Data from 77 participants were available for the intervention arms (males = 43, females = 34) 37 participants data (males = 20, females = 17) from the control arms. Intervention participants had all undergone 12 weeks of ILEX resistance training and changes in ILEX strength, pain (visual analogue scale; VAS), and disability (Oswestry disability index; ODI) measured. True inter-individual (i.e., between participants) variability in response was examined through calculation of difference in the standard deviation of change scores for both control and intervention arms. Intervention participants were classified into responder status using k-means cluster analysis for ILEX strength changes and using minimal clinically important change cut-offs for VAS and ODI. Change in average ILEX strength ranged 7.6 Nm (1.9%) to 192.1 Nm (335.7%). Change in peak ILEX strength ranged -12.2 Nm (-17.5%) to 276.6 Nm (169.6%). Participants were classified for strength changes as low (n = 31), medium (n = 36), and high responders (n = 10). Change in VAS ranged 12.0 mm to -84.0 mm. Participants were classified for VAS changes as negative (n = 3), non-responders (n = 34), responders (n = 15), and high responders (n = 19). Change in ODI ranged 18 pts to -45 pts. Participants were classified for ODI changes as negative (n = 2), non-responders (n = 21), responders (n = 29), and high responders (n = 25). Considerable variation exists in response to ILEX resistance training in CLBP. Clinicians should be aware of this and future work should identify factors prognostic of successful outcomes.

Individualized Physical Therapy Is Cost-Effective Compared With Guideline-Based Advice for People With Low Back Disorders

STUDY DESIGN

A cost-utility analysis within a randomized controlled trial was conducted from the health care perspective.

OBJECTIVE

The aim of this study was to determine whether individualized physical therapy incorporating advice is cost-effective relative to guideline-based advice alone for people with low back pain and/or referred leg pain (≥6 weeks, ≤6 months duration of symptoms).

SUMMARY OF BACKGROUND DATA

Low back disorders are a burdensome and costly condition across the world. Cost-effective treatments are needed to address the global burden attributable to this condition.

METHODS

Three hundred participants were randomly allocated to receive either two sessions of guideline-based advice alone (n = 144), or 10 sessions of individualized physical therapy targeting pathoanatomical, psychosocial and neurophysiological factors, and incorporating advice (n = 156). Data relating to health care costs, health benefits (EuroQol-5D) and work absence were obtained from participants via questionnaires at 5, 10, 26, and 52-week follow-ups.

RESULTS

Total health care costs were similar for both groups: mean difference $27.03 [95% confidence interval (95% CI): -200.29 to 254.35]. Health benefits across the 12-month follow-up were significantly greater with individualized physical therapy: incremental quality-adjusted life years = 0.06 (95% CI: 0.02-0.10). The incremental cost-effectiveness ratio was $422 per quality-adjusted life year gained. The probability that individualized physical therapy was cost-effective reached 90% at a willingness-to-pay threshold of $36,000. A saving of $1995.51 (95% CI: 143.98-3847.03) per worker in income was realized in the individualized physical therapy group relative to the advice group. Sensitivity and subgroup analyses all revealed a dominant position for individualized physical therapy; hence, the base case analysis was the most conservative.

CONCLUSION

Ten sessions of individualized physical therapy incorporating advice is cost-effective compared with two sessions of guideline-based advice alone for people with low back disorders.

LEVEL OF EVIDENCE

2.

Individualised physiotherapy as an adjunct to guideline-based advice for low back disorders in primary care: a randomised controlled trial

BACKGROUND

Many patients with low-back disorders persisting beyond 6 weeks do not recover. This study investigates whether individualised physiotherapy plus guideline-based advice results in superior outcomes to advice alone in participants with low-back disorders.

METHODS

This prospective parallel group multicentre randomised controlled trial was set in 16 primary care physiotherapy practices in Melbourne, Australia. Random assignment resulted in 156 participants receiving 10 sessions of physiotherapy that was individualised based on pathoanatomical, psychosocial and neurophysiological barriers to recovery combined with guideline-based advice, and 144 participants receiving 2 sessions of physiotherapist-delivered advice alone. Primary outcomes were activity limitation (Oswestry Disability Index) and numerical rating scales for back and leg pain at 5, 10, 26 and 52 weeks postbaseline. Analyses were by intention-to-treat using linear mixed models.

RESULTS

Between-group differences showed significant effects favouring individualised physiotherapy for back and leg pain at 10 weeks (back: 1.3, 95% CI 0.8 to 1.8; leg: 1.1, 95% CI 0.5 to 1.7) and 26 weeks (back: 0.9, 95% CI 0.4 to 1.4; leg: 1.0, 95% CI 0.4 to 1.6). Oswestry favoured individualised physiotherapy at 10 weeks (4.7; 95% CI 2.0 to 7.5), 26 weeks (5.4; 95% CI 2.6 to 8.2) and 52 weeks (4.3; 95% CI 1.4 to 7.1). Responder analysis at 52 weeks showed participants receiving individualised physiotherapy were more likely to improve by a clinically important amount of 50% from baseline for Oswestry (relative risk (RR=1.3) 1.5; 95% CI 1.2 to 1.8) and back pain (RR 1.3; 95% CI 1.2 to 1.8) than participants receiving advice alone.

CONCLUSIONS

10 sessions of individualised physiotherapy was more effective than 2 sessions of advice alone in participants with low-back disorders of ≥6 weeks and ≤6 months duration. Between-group changes were sustained at 12 months for activity limitation and 6 months for back and leg pain and were likely to be clinically significant.

CLINICAL TRIAL REGISTRATION

ACTRN12609000834257.

Complexity in the physiotherapy management of low back disorders: clinical and research implications

Over the past decade a wide variety of approaches for the management of low back disorders (LBD) have been developed and evaluated in clinical trials. As a consequence physiotherapists and researchers interested in LBD are faced with a range of issues to do with complexity. These issues will be explored and suggestions made to improve the delivery of high quality research evidence and better patient outcomes.